Slide Fastener

ABSTRACT

There is provided a slide fastener including a fastener chain and a slider. The slider includes upper and lower blades, a front end wall having a first front mouth and a second front mouth provided below the first front mouth, and one rear mouth. The slider is movable in a first direction to engage a pair of element rows, and in a second direction to disengage the pair of element rows. Each element has a base portion fixed to respective fastener tapes and a head portion configured to be engaged with the opposing elements. The head portion has a first head portion arranged at a side of upper surfaces of the tapes and a second head portion arranged at a side of lower surfaces of the tapes. The first head portion is formed to be offset from the second head portion in the first direction.

TECHNICAL FIELD

The present invention relates to a slide fastener in which a fastenerchain has continuous element rows fixed to fastener tapes and isconfigured to be engaged and disengaged by a slider of a type, whichcauses engagement to be occurred in an upward and downward direction.

BACKGROUND ART

From WO 2010/082291 (Patent Document 1), a slide fastener is disclosed,in which an element guide passage of a slider has right and leftshoulder mouths stepwise arranged in a front and back direction andconfigured, respectively, to allow a first element row and a secondelement row in a disengaged state to enter and exit therethrough, and arear mouth configured to allows the first and second element rows in anengaged state to enter and exit therethrough, and an extension length ofa front latch portion in the first element row is set to be shorter thanan extension length of a front latch portion of the second element row.

According to the invention described in Patent Document 1, when rightand left element rows are engaged with each other, the first element rowhaving a shorter extension length and the second element row having alonger extension length are introduced from the front side in such amanner that the rows are stepped relative to each other in the front andrear direction, and then the right and left element rows are obliquelymerged with each other in the front and back direction and the right andleft direction, thereby allowing the element rows to be easily engagedwith each other. Also, when the right and left element rows in theengaged state are disengaged from each other, the element rows areobliquely separated from each other in the front and back direction andthe right and left direction, thereby allowing the element rows to beeasily disengaged from each other.

PRIOR ART DOCUMENT Patent Document

Patent Document 1: WO 2010/082291

SUMMARY OF INVENTION Problems to be Solved by Invention

An object of the present invention is to provide a slide fastener, inwhich continuous element rows can be easily engaged with and disengagedfrom each other by a slider of a type, which causes engagement to beoccurred in an upward and downward direction.

Means for Solving Problems

A slide fastener according to one embodiment of the present inventionincludes:

a fastener chain including a pair of fastener stringers having a pair offastener tapes respectively having upper surfaces and lower surfacesopposite to the upper surfaces and element rows respectively constitutedof a plurality of elements fixed to respective edge portions of the pairof fastener tapes at a predetermined pitch, the fastener chain in whichthe element rows are arranged so as to oppose each other; and

a slider movable to engage and disengage the element rows with and fromeach other and including an upper blade arranged at a side of uppersurfaces, a lower blade arranged at a side of the lower surfaces, afront end wall connecting the upper blade with the lower blade andhaving a first front mouth for allowing the first element row to enterand exit therethrough and a second front mouth stepwise provided at theside of the lower surfaces relative to the first front mouth, forallowing the second element row to enter and exit therethrough, and onerear mouth for allowing the pair of element rows in an engaged state toenter and exit therethrough,

wherein each of the elements has a base portion fixed to the respectivefastener tapes and a head portion protruding from the base portion andconfigured to be engaged with the opposing elements,

wherein the head portion of each of the elements has a first headportion arranged at the side of the upper surfaces and a second headportion arranged at the side of the lower surfaces of the fastenertapes, and

wherein the first head portion is formed to be offset from the secondhead portion in the first direction.

In the slide fastener according to one embodiment of the presentinvention,

each of the elements has a neck portion located between the base portionand the head portion and having a width smaller than those of the baseportion and the head portion,

the neck portion of each of the elements has a first neck portionarranged at the side of the upper surfaces and a second neck portionarranged at the side of the lower surfaces of the fastener tapes, and

the first neck portion is formed to be offset from the second neckportion in the first direction.

In the slide fastener according to one embodiment of the presentinvention,

each of the elements includes:

-   -   a first protrusion portion formed on the first head portion,        which is located toward the respective lower surfaces and at a        side of the first direction;    -   a first recess portion formed on the first neck portion, which        is located toward the respective lower surfaces and at a side of        the first direction;    -   a second protrusion portion formed on the second head portion,        which is located toward the respective upper surfaces and at a        side of a second direction opposite to the first direction; and    -   a second recess portion formed on the second neck portion, which        is located toward the respective upper surfaces and at a side of        the second direction opposite to the first direction,

upon engaging of the pair of fastener stringers, the first protrusionportion of the elements located at one side is engaged with the secondrecess portion of the opposing elements, and

the first recess portion of the elements located at the one side isengaged with the second protrusion portion of the opposing elements.

An offset amount by which the first head portion is offset from thesecond head portion is 0.2 mm or greater and 0.3 mm or smaller, and

a ratio of the offset amount with respect to a dimension of the headportion of the elements along the first direction is 9% or greater and15% or smaller.

Advantageous Effects of Invention

According to the present invention, a slide fastener, in whichcontinuous element rows can be easily engaged with and disengaged fromeach other by a slider of a type, which causes engagement to be occurredin an upward and downward direction, can be provided.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front view showing a slide fastener constructed using afastener chain according to one embodiment of the present invention.

FIG. 2 is a view showing a disengaged state of the fastener chainaccording to one embodiment of the present invention.

FIG. 3 is a sectional view taken along a line A-A in FIG. 2.

FIG. 4 is a sectional view taken along a line B-B in FIG. 2.

FIG. 5 is a view showing an engaged state of elements of the fastenerchain according to one embodiment of the present invention.

FIG. 6 is a sectional view taken along a line C-C in FIG. 5.

FIG. 7 is a perspective view of a slider of a slide fastener accordingto one embodiment of the present invention.

FIG. 8 is a side view of a slider of the slide fastener according to oneembodiment of the present invention.

FIG. 9 is a views showing a state where the slide fastener of thepresent embodiment is being disengaged by the slider.

FIG. 10 is a view showing a state of a reference example where a slidefastener, which is reversed front to back and thus is different from thepresent embodiment, is being disengaged by a slider.

FIG. 11 is a view showing a state where the slide fastener of thepresent embodiment is being engaged by the slider.

FIG. 12 is a view showing a state of a reference example where a slidefastener, which is reversed front to back and thus is different from thepresent embodiment, is being engaged by a slider.

FIG. 13 is a view showing dimensions of an element 30 of the presentembodiment.

FIG. 14 is a graph showing crosswise strength against offset amount inTable 1.

FIG. 15 is a graph showing puncture strength against offset amount inTable 1.

FIG. 16 is a graph showing sliding resistance upon disengaging againstoffset amount in Table 2.

FIG. 17 is a graph showing sliding resistance upon engaging againstoffset amount in Table 3.

EMBODIMENTS OF INVENTION

Hereinafter, a fastener chain 10 and a slide fastener 1 according toembodiments of the present invention will be described in detail on thebasis of the accompanying drawings.

FIG. 1 is a front view showing a slide fastener constructed using afastener chain according to one embodiment of the present invention.

The slide fastener 1 as explained in the present embodiment has a pairof right and left fastener chains 10 including a first fastener stringer11, in which a first element row 31 constituted of a plurality of firstelements 301 is attached to a first fastener tape 21, and a secondfastener stringer 12, in which a second element row 32 constituted of aplurality of second elements 302 is attached to a second fastener tape22, and a slider 6 configured to be slid along the right and leftcontinuous element rows 31 and 32 and thus to engage and disengage theelements 301 and 302 of the continuous element rows 31 and 32 with andfrom each other.

Also, in the following description, a direction in which the continuouselement rows are provided along a longitudinal direction of the fastenerchain 10 is referred to as a front and rear direction, a direction inwhich the slider 6 is slid to engage the right and left continuouselement rows 31 and 32 with each other is referred to as a frontdirection, and a direction in which the slider 6 is slide to disengagethe element rows from each other is referred to as a rear direction.Also, a right and left direction refers to a direction horizontal to aplane of the fastener chain 10 and perpendicular to the front and reardirection. A direction perpendicular to a plane defined by the front andrear direction and the right and left direction is referred to as afront and back direction, a side of the fastener chain 6 on which a pulltab of the slider 6 exists is referred to as a front surface, and a sideopposite thereto is referred to as a back surface. The front and backdirection can be also referred to as an upward and downward direction,and correspondingly, the front surface can be also referred to as anupper surface and the back surface can be also referred to as a lowersurface.

Further, the front direction and the rear direction may beinterchangeably referred to as a first direction and a second direction,respectively. The second direction is a direction opposite to the firstdirection. In addition, the front surface and the back surface may beinterchangeably referred to as a first surface and a second surface,respectively.

The fastener chain 10 is constituted of a pair of fastener stringers 11and 12. The fastener stringers 11 and 12 have a pair of fastener tapes20 each having a upper surface 21 a and a lower surface 21 b opposite tothe upper surface 21 a, and element rows 31 and 32 respectivelyconstituted of a plurality of elements 301 and 302 fixed to respectiveedge portions 23 of the pair of fastener tapes 20 at a predeterminedpitch. The element rows 31 and 32 are arranged to oppose each other.

Also, a top stop, not shown, is fixed to an upper end of each ofcontinuous element rows 31 and 32 and one bottom stop, not shown, isfixed to lower ends of the continuous element rows 31 and 32. Thus, itcan be prevented that the slider 6 is pulled out from the upper andlower ends of the continuous element rows 31 and 32. Alternatively, inthe present embodiment, instead of the bottom stop, an opener, such as aseparable pin and a retainer pin, may be fixed.

FIG. 2 is a view showing a disengaged state of the fastener chainaccording to one embodiment of the present invention. FIG. 3 is asectional view taken along a line A-A in FIG. 2. FIG. 4 is a sectionalview taken along a line B-B in FIG. 2.

The first elements 301 have a head portion 301 a located at the mostoutward side remotest from a first edge portion 231 of the firstfastener tape 21 in the right and left direction of the fastener chain10, a neck portion 301 b located inward relative to the head portion 301a (close to the first edge portion 231) but outward relative to thefirst edge portion 231, and a base portion 301 c located inward relativeto the neck portion 301 b and sandwiching the first edge portion 231.Also, the first elements 301 have a first half portion 311 arranged at aside of the upper surface 21 a of the first fastener tape 21 and asecond half portion 321 arranged at a side of the lower surface 21 b ofthe first fastener tape 21. The first half portion 311 and the secondhalf portion 321 are integrally formed with each other to sandwich thefirst fastener tape 21 from upper and lower sides thereof

The first half portion 311 has a first base portion 311 c in contactwith the upper surface 21 a of the first fastener tape 21, a first neckportion 311 b protruding from the first base portion 311 c and extendingtoward the outside of the first fastener tape 21, and a first headportion 311 a formed on a distal end of the first neck portion 311 b.The second half portion 321 has a second base portion 321 c in contactwith the lower surface 21 b of the first fastener tape 21, a second neckportion 321 b protruding from the second base portion 321 c andextending toward the outside of the first fastener tape 21, and a secondhead portion 321 a formed on a distal end of the second neck portion 321b. The first base portion 311 c and the second base portion 321 csandwich the first edge portion 231 from the upward and downwarddirections.

The first elements 301 of the present embodiment are formed in a statewhere the first half portion 311 is offset relative to the second halfportion 321 in the front direction or a state where the second halfportion 321 is offset relative to the first half portion 311 in the reardirection. A first protrusion portion 331 a is formed in front of thefirst head portion 311 a of the first half portion 311, a first recessportion 331 b is formed in front of the first neck portion 311 b, and afirst stepped portion 331 c is formed in front of the first base portion311 c. A second protrusion portion 341 a is formed in the rear of thesecond head portion 321 a of the second half portion 321, a secondrecess portion 341 b is formed in the rear of the second neck portion321 b, and a second stepped portion 341 c is formed in the rear of thesecond base portion 321 c.

The second fastener stringer 12 of the present embodiment is formed tobe symmetric to the first fastener stringer 11 in the right and leftdirection, and components thereof are the same as those of the firstfastener stringer 11. The second elements 302 have a head portion 302 alocated at the most outward side remotest from a second edge portion 232of the second fastener tape 22 in the right and left direction of thefastener chain 10, a neck portion 302 b located inward relative to thehead portion 302 a (close to the second edge portion 232) but outwardrelative to the second edge portion 232, and a base portion 302 clocated inward relative to the neck portion 302 b and sandwiching thesecond edge portion 231. Also, the second elements 302 have a first halfportion 312 arranged at the side of the upper surface 21 a of the secondfastener tape 22 and a second half portion 322 arranged at the side ofthe lower surface 21 b of the second fastener tape 22. The first halfportion 312 and the second half portion 322 are integrally formed witheach other to sandwich the second fastener tape 22 from upper and lowersides thereof

The first half portion 312 has a first base portion 312 c in contactwith the upper surface 21 a of the second fastener tape 22, a first neckportion 312 b protruding from the first base portion 312 c and extendingtoward the outside of the second fastener tape 22, and a first headportion 312 a formed on a distal end of the second neck portion 312 b.The second half portion 322 has a second base portion 322 c in contactwith the lower surface 21 b of the second fastener tape 22, a secondneck portion 322 b protruding from the second base portion 322 c andextending toward the outside of the second fastener tape 22, and asecond head portion 322 a formed on a distal end of the second neckportion 322 b. The first base portion 312 c and the second base portion322 c sandwich the second edge portion 232 from the upward and downwarddirections.

The second elements 302 of the present embodiment are formed in a statewhere the first half portion 312 is offset in the front direction or astate where the second half portion 322 is offset in the rear direction.A first protrusion portion 332 a is formed in front of a side of thefirst half portion 312 opposite to the first head portion 312 a, a firstrecess portion 332 b is formed in front of a side thereof opposite tothe first neck portion 312 b, and a first stepped portion 332 c isformed in front of a side thereof opposite to the first base portion 312c. A second protrusion portion 342 a is formed in the rear of a side ofthe second half portion 312 opposite to the second head portion 322 a, asecond recess portion 342 b is formed in the rear of a side thereofopposite to the second neck portion 322 b, and a second stepped portion342 c is formed in the rear of a side thereof opposite to the secondbase portion 322 c.

FIG. 5 is a view showing an engaged state of the fastener chainaccording to one embodiment of the present invention. FIG. 6 is asectional view taken along a line C-C in FIG. 5.

In the engaged state of the fastener chain 10 of the present embodiment,as shown in FIG. 5, the head portion 301 a of the first element row 31and the neck portion 302 b of the second element row 32, which areadjacent to each other in the front and rear direction, are engaged witheach other, and the neck portion 301 b of the first element row 31 andthe head portion 302 a of the second element row 32, which are adjacentto each other in the front and rear direction, are engaged with eachother.

Also, as shown in FIG. 6, the first protrusion portion 331 a of thefirst element 301 opposes to the second recess portion 342 b of thesecond element 302 and the second protrusion portion 341 a of the firstelement 301 opposes the first recess portion 332 b of the second element302, and although not shown, the first recess portion 331 b of the firstelement 301 opposes the second protrusion portion 342 a of the secondelement 302 and the second recess portion 341 b of the first element 301opposes the first protrusion portion 332 a of the second element 302.

Accordingly, the first element row 31 and the second element row 32opposing each other can be exactly engaged with each other.

Next, the slider 6 of the fastener chain 10 of the present embodimentwill be described.

FIG. 7 is a perspective view of a slider of a slide fastener accordingto one embodiment of the present invention. FIG. 8 is a side view of theslider of the slide fastener according to one embodiment of the presentinvention.

Referring to FIGS. 7 and 8, the slider 6 according to the presentembodiment includes, as a basis structure, an upper blade 61, a lowerblade 62, a first side wall 64 having a first guide groove 63 forguiding the first fastener tape 21 shown in FIG. 1, a second side wall66 having a second guide groove 65 for guiding the second fastener tape2, a front end wall 69 connecting the upper blade 61 with the lowerblade 62 and provided with a first front mouth 67 for allowing the firstelement row 31 in the disengaged state shown in FIG. 2 to enter and exittherethrough and a second front mouth 68 located below the first frontmouth 67 for allowing the second element row 32 to enter and exittherethrough, and one rear mouth 70 for allowing the pair of elementrows 31 and 32 in the engaged state shown in FIG. 1 to enter and exittherethrough.

A pull tab attaching portion 75 is provided on an upper surface of theupper blade 61. Although in the present embodiment, the pull tabattaching portion 75 has a gate shape of extending in a slidingdirection in a cantilever shape with one end thereof fixed, theinvention is not limited to such a configuration, and thus a pull tabattaching portion having any other shapes as known to those skilled inthe art may be employed. Also, a pull tab having an annular portion atone end thereof may be prepared and then the pull tab may be pivotallyattached to the pull tab attaching portion 75 via the annular portion.Further, a distal end of the pull tab attaching portion 75 may becrimped downward (i.e., a direction of approaching the distal end to theupper blade), thereby preventing a pull tab, not shown, from beingeasily separated from the pull tab attaching portion 75.

Referring to FIG. 8, two front mouths 67 and 68 and one rear mouth 70are connected by a generally Y-shaped element guide passage 80 formedinside the slider to be furcated in the upward and downward directionalong the guide grooves 63 and 65, respectively. The element guidepassage 80 is defined by an inner surface of the upper blade 61, aninner surface of the lower blade 62, inner surfaces of right and leftside walls 64 and 66, and an element guide post 71.

The inner surface of the upper blade 61 defining the element guidepassage 80 has an inclined surface 81 inclined downward from the firstfront mouth 67 on the front surface side and a horizontal surface 83connected to the inclined surface 81 and configured to cause the elementrows to be engaged with each other. Also, the inner surface of the lowerblade 62 has an inclined surface 82 inclined upward from the secondfront mouth 68 on the back surface side and a horizontal surface 84connected to the inclined surface 82 and configured to cause the elementrows to be engaged with each other. A rear end of each of horizontalsurfaces 83 and 84 is connected to the rear mouth 70. Each of connectionportions between the inclined surfaces 81 and 82 and the horizontalsurfaces 83 and 84 is preferably formed in a curved line shape in orderto allow a smooth movement of the element rows.

The guide grooves 63 and 65 have an inclined portion and a horizontalportion corresponding to shapes of the inner surface of the upper blade61 and the inner surface of the lower blade 62, and connection portionstherebetween are preferably formed in a curved line shape in order toallow a smooth movement of the fastener tapes. Specifically, the firstguide groove 63 formed in the first side wall 64 has a front endconnected to the first front mouth 67 on the front surface side, aninclined portion connected to the front end and inclined downward, ahorizontal portion connected to the inclined portion and configured tocause the element rows to be engaged with each other and a rear endconnected to the horizontal portion and also connected to the rear mouth70, and the inclined portion and the horizontal portion are formed to beparallel to the inner surface of the upper blade 61. The second guidegroove 65 formed in the second side wall 66 has a front end connected tothe second front mouth 68 on the back surface side, an inclined portionconnected to the front end and inclined forward, a horizontal portionconnected to the inclined portion and configured to cause the elementrows to be engaged with each other and a rear end connected to thehorizontal portion and also connected to the rear mouth 70, and theinclined portion and the horizontal portion are formed to be parallel tothe inner surface of the lower blade 62.

Next, operations when elements of the fastener chain 10 of the presentembodiment are disengaged by the slider 6 will be described.

FIG. 9 is a views showing a state where the slide fastener of thepresent embodiment is being disengaged by the slider.

When the slider 6 is moved in a direction of an arrow A1, a pair ofelement rows engaged with each other enters the slider 6 through therear mouth 70. The element rows, which are initially engaged with eachother, are disengaged by the element guide post 71 formed in the elementguide passage 80.

In the slider 6 according to the present embodiment, each of two frontmouths 67 and 68 exists to straddle the center line in the right andleft direction, and thus the two front mouths 67 and 68 create anoverlapped portion in the right and left direction. Accordingly, theelement rows 31 and 32 are disengaged from each other in the front andback direction.

Upon disengaging, the first elements 301 directed toward the first frontmount 67 on the front surface side are pulled in a direction of an arrowA2 as shown in FIG. 9. Then, the second protrusion portion 341 a of thefirst element 301 and the first recess portion 332 b of the secondelement 302 come in contact with each other, and the second recessportion 341 b of the first element 301 and the first protrusion portion332 a of the second element 302, not shown, come in contact with eachother. The first protrusion portion 332 a of the first element 301 andthe second recess portion 342 b of the second element 302 are spacedfrom each other, and the first recess portion 331 b of the first element301 and the second protrusion portion 342 a of the second element 302,not shown, are spaced from each other.

In order to cause the first element 301 to be spaced from the secondelement 302, a movement thereof in a direction of an arrow A3 isrequired. In a case of the present embodiment, the first element 301 ispulled in the direction of the arrow A2 after the second protrusionportion 341 a and the second recess portion 341 b of the first element301 come in contact with the first recess portion 332 b and the firstprotrusion portion 332 a of the second element 302, respectively. Then,the first element 301 is inclined in the direction of the arrow A3 tohave an angle allowing the first element 301 to be easily slide relativeto the second element 302.

A force along the arrow A2 exerted on the first element 301 and amovement thereof in the direction of the arrow A3 shown in FIG. 9 havethe same rotating direction, and accordingly the first element 301 canbe easily moved in the direction of the arrow A3 by a force in thedirection A1 of pulling the slider 6. Thus, as the slider 6 is furthermoved, the first elements 301 and the second elements 302 can be easilyspaced from each other.

FIG. 10 is a view showing a state of a reference example where a slidefastener, which is reversed front to back and thus is different from thepresent embodiment, is being disengaged by a slider.

In a case of the example in which orientation of the elements isdifferent from that of the present embodiment as shown in FIG. 10, ifupon disengaging, a slider 6 is pulled in a direction of an arrow A11 tobe moved rearward, second elements 302 directed toward a first frontmouth 67 on the front surface side are moved in a direction of an arrowA12. Then, a first protrusion portion 331 a of a first element 301 and asecond recess portion 342 b of a second element 302 come in contact witheach other, and a first recess portion 331 b of the first element 301and the second protrusion portion 342 a of the second element 302, notshown, come in contact with each other. Then, a force causing rotationthereof about such contact points is occurred on the second element 302,and thus the second protrusion portion 341 a of the first element 301and the second recess portion 342 b of the second element 302 come incontact with each other and the second recess portion 341 b of the firstelement 301 and the second protrusion portion 342 a of the secondelement 302, not shown, also come in contact with each other.

In this case, because the first protrusion portion 331 a of the firstelement 301 and the second recess portion 342 b of the second element302 come in contact with each other and the first recess portion 331 bof the first element 301 and the second protrusion portion 342 a of thesecond element 302, not shown, come in contact with each other, it isdifficult to space the first element 301 and the second element 302 fromeach other.

Next, operations when elements of the fastener chain 10 of the presentembodiment are engaged by the slider 6 will be described.

FIG. 11 is a view showing a state where the slide fastener of thepresent embodiment is being engaged by the slider.

When the slider 6 is moved in a direction of an arrow B1, the firstelements 301 in the disengaged state enter through the first front mouth67 on the front surface side and the second elements 302 enter throughthe second front mouth 68 on the back surface side. As the firstelements 301 and the second elements 302 are guided by the element guidepassage 80, the first elements 301 and the second elements 302 areengaged in front of the rear mouth 70 and then are discharged throughthe rear mouth 70.

Upon engaging, the second elements 302, which have entered through thesecond front mouth 68 on the back surface side and then passed over theelement guide post 71, are pulled in a direction of an arrow B2 as shownin FIG. 11. Then, the first protrusion portion 331 a of the firstelement 301 and the second recess portion 342 b of the second element302 come in contact with each other and the first recess portion 331 bof the first element 301 and the second protrusion portion 342 a of thesecond element 302, not shown, come in contact with each other, therebycausing the second element 302 to be moved in a direction of an arrowB3.

A force along the arrow B2 exerted on the second element 302 and amovement thereof in the direction of the arrow B3 shown in FIG. 11 havethe same rotating direction, and accordingly the second element 302 canbe easily moved in the direction of the arrow B3 by a force in thedirection B1 of pulling the slider 6. Thus, as the slider 6 is furthermoved, the first elements 301 and the second elements 302 can be easilyengaged with each other.

FIG. 12 is a view showing a state of a reference example where a slidefastener, which is reversed front to back and thus is different from thepresent embodiment, is being engaged by a slider.

In a case of the example in which orientation of the elements isdifferent from that of the present embodiment as shown in FIG. 12, ifupon engaging, a slider 6 is pulled and moved in a direction of an arrowB11, a first element 301, which has passed over the element guide post71, of the first elements 301 directed toward a rear mouth 70, is movedin a direction of an arrow

B12.

Then, a surface of a first head portion 311 a of the first element 301comes in contact with a second recess portion 332 b of a second element302, and thus there is a possibility that engagement of the firstelement 301 with the second element 302 is interfered.

Next, an offset dimension (also referred to as an offset amount) betweenthe first half portion 311 and the second half portion 322 of eachelement of the present embodiment will be described. Meanwhile, theoffset amount a means a dimension by which the first head portion 311 ais offset from the second head portion 321 a, and also a dimension bywhich the first neck portion (311 b) is offset from the second neckportion (321 b).

FIG. 13 is a view showing dimensions of an element 30 of the presentembodiment. Meanwhile, in the following, dimensions of the first element301 will be described by way of example, but the same can be alsoapplied to the second element 302.

As shown in FIG. 13, the largest dimension of the head portion 301 a ofthe first element 301 in the front and rear direction is indicated as L,the offset amount is indicated as a, and the smallest dimension of theneck portion 301 b in the front and rear direction is indicated as b.Meanwhile, the dimension L in the front and rear direction can beinterchangeably referred to as a dimension along a first direction or adimension along a second direction. Herein, the first head portion 311 aof the first half portion 311 and the second head portion 321 a of thesecond half portion 321 have the same dimensions. Also, the first neckportion 311 b and the second neck portion 321 b have the samedimensions.

The offset amount a between the first half portion 311 and the secondhalf portion 321 of the first element 301 is a dimension of the firstprotrusion portion 331 a and the second protrusion portion 341 a of thefirst element 301 in the front and rear direction, if stated in anotherway. Meanwhile, the offset amount a is the same as a dimension of thefirst recess portion 331 b and the second recess portion 341 b.

In order to measure the offset amount a, a dimension from a front endedge of the first head portion 311 a of the first half portion 311 to afront end edge of the second head portion 321 a of the second halfportion 321, or a dimension from a rear end edge of the second headportion 321 a of the second half portion 321 to a rear end edge of thefirst head portion 311 a of the first half portion 311 is measured.Alternatively, the offset amount a may be obtained by measuring adimension from a front end edge of the first neck portion 311 b of thefirst half portion 311 to a front end edge of the second neck portion321 b of the second half portion 321, or measuring a dimension from arear end edge of the second neck portion 321 b of the second halfportion 321 to a rear end edge of the first neck portion 311 b of thefirst half portion 311.

Table 1 shows results of strength tests of the chain performed withregard to two items, i.e., crosswise strength and puncture strength.Also, FIG. 14 is a graph showing crosswise strength against offsetamount in Table 1. FIG. 15 is a graph showing puncture strength againstoffset amount in Table 1. Herein, the crosswise strength means amagnitude of resistance when right and left fastener tapes are pulled ata predetermined speed in right and left directions opposite to eachother in a state where the fastener chain is engaged. Also, the puncturestrength means a magnitude of resistance when elements are verticallypushed up relative to the tape surface in a state where the fastenerchain is engaged. The units are [N]. Five fastener chains for each ofcrosswise strength and puncture strength are prepared, and a magnitudeof resistance for each is recorded and a maximum value (max), a minimumvalue (min) and an average (Ave) are shown.

TABLE 1 Crosswise Strength (N) Puncture Strength (N) 0.1 0.2 0.3 0.4 0.10.2 0.3 0.4 mm mm mm mm mm mm mm mm Ave 221 411 421 395 219 242 260 243max 420 422 429 414 239 250 269 255 min 24 403 400 367 186 238 246 228

As shown in FIG. 14, the fastener chains have an average of crosswisestrength below a predetermined reference value of 400 N in cases wherethe offset amount is 0.1 mm and 0.4 mm. This cannot be said that thefastener chains has a sufficient strength, and accordingly, it ispreferable that the offset amount a of the fastener chain satisfy thefollowing equation (1).

0.2≦a≦0.3  (1)

Also, a ratio of the offset amount a with respect to the dimension L ofthe head portion 301 a of the first element 301 may be prescribed. Inthis case, it is preferable that the ratio satisfy the followingequation (2)

9%≦a/L≦15%  (2)

More preferably, the ratio may satisfy 9.6%≦a/L≦14.4%.

According to this equation, if the ratio is smaller than 9%, asufficient crosswise strength or puncture strength cannot be obtained,and if the ratio is greater than 15%, a sliding resistance upon engagingand disengaging is increased. Herein, a cause of increasing the slidingresistance is that for example, in case where right and left elementsare disengaged from each other inside the slider, the right and leftelements are disengaged from the engaged state in a posture where theelements are inclined so that front mouths of the slider are separatedfrom each other in the upward and downward direction. Thus, if a/L isgreater, in order to disengage the elements from each other, theelements have to be inclined by largely changing the posture thereof,thereby increasing the sliding resistance. Upon engaging, the right andleft elements in the disengaged state are changed in posture to becomefrom the inclined state to a horizontal state, thereby increasing thesliding resistance, like upon disengaging.

In the present embodiment, preferably, L=2.1 mm. Meanwhile, as areference, a dimension (width) b of the neck portion of the presentembodiment in the front and rear direction is set to 1.2 mm.

Table 2 shows sliding resistances upon disengaging of slide fasteners.Table 3 shows sliding resistances upon engaging of slide fasteners. FIG.16 is a graph showing sliding resistance upon disengaging against offsetamount in Table 2. FIG. 17 is a graph showing sliding resistance uponengaging against offset amount in Table 3. Herein, the slidingresistance upon engaging is a magnitude of resistance when a pull tab ofa slider of a slide fastener is pulled and moved in a direction ofengaging the slide fastener, and the sliding resistance upon disengagingis a magnitude of resistance when the pull tab of the slider of theslide fastener is pulled and moved in a direction of disengaging theslide fastener.

In Tables, “0.2 mm Second direction” is a case where an offset amount aof elements is 0.2 mm and a first half portion 311 is offset from asecond half portion 321 in the rear direction (second direction), and“0.2 mm First direction” is a case where an offset amount a of elementsis 0.2 mm and a first half portion 311 is offset from a second halfportion 321 in the front direction (first direction). Also, “0.3 mmSecond direction” is a case where an offset amount a of elements is 0.3mm and a first half portion 311 is offset from a second half portion 321in the rear direction (second direction), and “0.3 mm First direction”is a case where an offset amount a of elements is 0.3 mm and a firsthalf portion 311 is offset from a second half portion 321 in the frontdirection (first direction). The unit is [N].

Table 2 shows a magnitude of resistance of a slider when a slidefastener in an engaged state is disengaged by the slider. Five slidefasteners are prepared, and a magnitude of resistance when the slider isslid is recorded and a maximum value (max), a minimum value (min) and anaverage (Ave) are shown.

TABLE 2 Offset Amount 0.2 mm 0.2 mm 0.3 mm a of Element Second FirstSecond 0.3 mm Offset Direction Direction Direction Direction FirstDirection Ave 9.48 8.34 16.24 11.56 max 9.93 8.92 19.14 12.97 min 9.027.75 13.34 10.14

Table 3 shows a magnitude of resistance of a slider when a slidefastener in a disengaged state is engaged by the slider. Five slidefasteners are prepared, and a magnitude of resistance when the slider isslid is recorded and a maximum value (max), a minimum value (min) and anaverage (Ave) are shown.

TABLE 3 Offset Amount 0.2 mm 0.2 mm 0.3 mm a of Element Second FirstSecond 0.3 mm Offset Direction direction direction direction Firstdirection Ave 8.30 7.96 9.89 7.63 Max 8.86 8.55 10.69 8.18 Min 7.74 7.369.09 7.07

As shown in FIGS. 16 and 17, in each case of having the same offsetamount of 0.2 mm or 0.3 mm, a sliding resistance of slide fasteners inwhich a first half portion 311 of a first element 301 is offset from asecond half portion 321 in the front direction (first direction) asshown in FIG. 13 is smaller than a sliding resistance of slide fastenersin which a first half portion 311 of a first element 301 is offset froma second half portion 321 in the rear direction (second direction). Inother words, if offset amounts are the same, slide fasteners in whichthe first half portion 311 of the first element 301 is offset from thesecond half portion 321 in the front direction (first direction) can beslid more smoothly than slide fasteners in which the first half portion311 of the first element 301 is offset from the second half portion 321in the rear direction (second direction). Meanwhile, as described above,the same results are also obtained for the second element 302.

As described above, the slide fastener 1 of the present embodimentincludes a fastener chain 10 including a pair of fastener stringers 11and 12 having a pair of fastener tapes 21 and 22 respectively havingupper surfaces 21 a and 22 a and lower surfaces 21 b and 22 b oppositeto the upper surfaces 21 a and 22 a and element rows respectivelyconstituted of a plurality of elements 301 and 302 fixed to respectiveedge portions 23 of the pair of fastener tapes 21 and 22 at apredetermined pitch, in which the element rows 31 and 32 are arranged soas to oppose each other; and a slider 6 movable to engage and disengagethe element rows 31 and 32 with and from each other and including anupper blade 61 arranged at a side of the upper surfaces 21 a and 22 aand configured to allow a pull tab 76 to be attached thereon, a lowerblade 62 arranged at a side of the lower surfaces 21 b and 22 b, a frontend wall 69 connecting the upper blade 61 with the lower blade 62 andhaving a first front mouth 67 for allowing the first element row 31 toenter and exit therethrough and a second front mouth 68 provided at theside of the lower surfaces relative to the first front mouth 67, forallowing the second element row 32 to enter and exit therethrough, andone rear mouth 70 for allowing the pair of element rows 31 and 32 in anengaged state to enter and exit therethrough. In the front end wall, thesecond front mouth 68 is provided to be stepped relative to the firstfront mouth 67 in the upward and downward and to be positioned below thefirst front mouth 67.

Each of the elements 301 and 302 has a base portion 301 c and 302 cfixed to the respective fastener tapes 2 and a head portion 301 a and302 a protruding from the base portion 301 c and 302 c and configured tobe engaged with opposing elements 301 and 302, and the head portion 301a and 302 a of each of the elements 301 and 302 has a first head portion311 a and 312 a arranged at the side of the upper surfaces 21 a and 22a, and a second head portion 321 a and 321 b arranged at the side of therespective lower surfaces 21 b and 22 b of the fastener tapes 21 and 22.The first head portion 311 a and 312 a is formed to be offset from thesecond head portion 321 a and 322 a in a first direction along which theslider 6 is moved when engaging the element rows 31 and 32 with eachother. A slide fastener, in which continuous element rows 31 and 32 canbe easily engaged with and disengaged from each other by a slider 6 of atype, which causes engagement to be occurred in the upward and downwarddirection, can be provided.

Also, according to the slide fastener 1 of the present embodiment, eachof the elements 301 and 302 has a neck portion 301 b and 302 b locatedbetween the base portion 301 c and 302 c and the head portion 301 a and302 a and having a width as a dimension in the front and rear directionsmaller than those of the base portion 301 c and 302 c and the headportion 301 a and 302 a, and the neck portion 301 a and 302 a of each ofthe elements 301 and 302 has a first neck portion 311 b and 312 barranged at the side of the lower surfaces 21 a and 22 a and a secondneck portion 321 b and 322 b arranged at the side of the lower surfaces21 b and 22 b of the fastener tapes 20. Also, the first neck portion 311b and 312 b is formed to be offset from the second neck portion 321 band 322 b in the first direction when the element rows 31 and 32 areengaged with each other. Accordingly, a slide fastener which can be moreeasily and stably engaged and disengaged can be provided.

Further, according to the slide fastener 1 of the present embodiment,each of the elements 301 and 302 has a first protrusion portion 331 aand 332 a formed on a side of the first head portion 311 a and 312 a,which is located toward the respective lower surfaces 21 b and 22 b andfaces the first direction, a first recess portion 331 b and 332 b formedon a side of the first neck portion 311 b and 312 b, which is locatedtoward the respective lower surfaces 21 b and 22 b and faces the firstdirection, a second protrusion portion 341 a and 342 a formed on a sideof the second head portion 321 a and 322 a, which is located toward therespective upper surfaces 21 a and 22 a and faces a second directionopposite to the first direction, and a second recess portion 341 b and342 b formed on a side of the second neck portion 321 b and 322 b, whichis located toward the respective upper surfaces 21 a and 22 a and facesthe second direction opposite to the first direction. Also, uponengaging of the pair of fastener stringers, the first protrusion portion331 a and 332 a of the elements 301 and 302 located on one side isengaged with the second recess portion 341 b and 342 b of the opposingelements 301 and 302, and the first recess portion 331 b and 332 b ofthe elements 301 and 302 located on the one side is engaged with thesecond protrusion portion 341 a and 342 a of the opposing elements 301and 302. Accordingly, a slide fastener which can be stably engaged anddisengaged can be provided.

Further, according to the slide fastener 1 of the present embodiment, anoffset amount a by which the first head portion 311 a and 312 a isoffset from the second head portion 321 a and 322 a is 0.2 mm or greaterand 0.3 mm or smaller and a ratio a/L of the offset amount a withrespect to a dimension L of the head portion 301 a and 302 a of theelements 301 and 302 along the first direction is 9% or greater and 15%or smaller. Accordingly, a slide fastener 1 which strengths required forthe fastener are sufficient and a sliding resistance is small can beobtained. If the ratio is smaller than 9%, sufficient strengths cannotbe obtained, and if the ratio is greater than 15%, the slidingresistance is increased.

Although various embodiments of the present invention have beendescribed in the foregoing, the present invention is not limited to theforegoing embodiments, and accordingly, any other embodimentsconstructed by appropriately combining configurations of the foregoingembodiments are intended to be encompassed by the scope of theinvention.

DESCRIPTION OF REFERENCE NUMERALS

-   -   301 . . . First Element    -   302 . . . Second Element    -   301 a, 302 a . . . Head Portion    -   301 b, 302 b . . . Neck Portion    -   301 c, 302 c . . . Base Portion    -   311, 312 . . . First Half Portion    -   311 a, 312 a . . . First Head Portion    -   311 b, 312 b . . . First Neck Portion    -   311 c, 312 c . . . First Base Portion    -   321, 322 . . . Second Half Portion    -   321 a, 322 a . . . Second Head Portion    -   321 b, 322 b . . . Second Neck Portion    -   321 c, 322 c . . . Second Base Portion    -   331 a, 332 a . . . First Protrusion Portion    -   331 b, 332 b . . . First Recess Portion    -   331 c, 332 c . . . First Stepped Portion    -   341 a, 342 a . . . Second Protrusion Portion    -   341 b, 342 b . . . Second Recess Portion    -   341 c, 342 c . . . Second Stepped Portion    -   6 . . . Slider    -   1 . . . Slide Fastener

1. A slide fastener, comprising: a fastener chain comprising a pair offastener stringers having a pair of fastener tapes respectively havingupper surfaces and lower surfaces opposite to the upper surfaces andelement rows respectively constituted of a plurality of elements fixedto respective edge portions of the pair of fastener tapes at apredetermined pitch, the fastener chain in which the element rows arearranged so as to oppose each other; and a slider including an upperblade arranged at a side of the upper surfaces, a lower blade arrangedat a side of the lower surfaces, a front end wall connecting the upperblade with the lower blade and having a first front mouth for allowingthe first element row to enter and exit therethrough and a second frontmouth provided at the side of the lower surfaces relative to the firstfront mouth, for allowing the second element row to enter and exittherethrough, and one rear mouth for allowing the pair of element rowsin an engaged state to enter and exit therethrough, wherein the slideris movable in a first direction, along which the slider is moved toengage the element rows with each other, and in a second directionopposite to the first direction, along which the slider is moved todisengage the element rows from each other, wherein each of the elementshas a base portion fixed to the respective fastener tapes and a headportion protruding from the base portion and configured to be engagedwith the opposing elements; wherein the head portion of each of theelements has a first head portion arranged at the side of the uppersurfaces and a second head portion arranged at the side of the lowersurfaces of the fastener tapes, wherein the first head portion is formedto be offset from the second head portion in the first direction.
 2. Theslide fastener according to claim 1, wherein each of the elements has aneck portion located between the base portion and the head portion andhaving a width smaller than those of the base portion and the headportion, wherein the neck portion of each of the elements has a firstneck portion arranged at the side of the upper surfaces and a secondneck portion arranged at the side of the lower surfaces of the fastenertapes, wherein the first neck portion is formed to be offset from thesecond neck portion in the first direction.
 3. The slide fasteneraccording to claim 2, wherein each of the elements comprises: a firstprotrusion portion formed on the first head portion at a side of thefirst direction; a first recess portion formed on the first neck portionat a side of the first direction; a second protrusion portion formed onthe second head portion at a side of the second direction; and a secondrecess portion formed on the second neck portion at a side of the seconddirection, wherein upon engaging of the pair of fastener stringers, thefirst protrusion portion of the elements located at one side is engagedwith the second recess portion of the opposing elements, and wherein thefirst recess portion of the elements located at the one side is engagedwith the second protrusion portion of the opposing elements.
 4. Theslide fastener according to claim 1, wherein an offset amount of thefirst head portion from the second head portion is 0.2 mm or greater and0.3 mm or smaller, and wherein a ratio of the offset amount with respectto a dimension of the head portion of the elements along the firstdirection is 9% or greater and 15% or smaller.